508 Narcolepsy Associated With a History of Head Injury: A Retrospective Review

Abstract

Abstract Introduction Head injuries are becoming much more prevalent and may be secondary to sports injuries, motor vehicle accidents, falls, domestic violence, assault, and military blast explosions. Sleepiness may occur acutely and/or chronically after a head injury. Chronic hypersomnia may be overlooked or under-reported in those with a history of head injury, and the association may not be made. Hypersomnia can occur in those with mild, moderate, and severe head injuries, with or without loss of consciousness. The pathophysiology/neuropathology of sleep-wake disturbances after Traumatic Brain Injury was discussed by Lim and Baumann 2020 in their Up To Date review entitled “Sleep-wake disorders in patients with traumatic brain injury”. They reported possible abnormalities in orexin/hypocretin, decreased histaminergic neurons, melatonin abnormalities, decreased serotonergic neurons, decreased noradrenergic neurons, and structural brain changes that can play a role. It is also possible that a head injury occurs in someone predisposed to the development of narcolepsy or that the sleepiness of undiagnosed narcolepsy leads to increased injuries. Methods A retrospective review of charts from 2013 to 2020 revealed 176 patients diagnosed with narcolepsy in our psychiatric/sleep outpatient practice. Information on head injuries was obtained by questionnaires completed by the patient and/or interview with staff. Narcolepsy was diagnosed by PSG/MSLT and/or DSM-V criteria of narcolepsy. Results Of the 176 patients diagnosed with narcolepsy, 125 were female (71%) and 51 were male (29%). The age range was 11 to 75 years, with an average age of 39 years old. Cataplexy was present in 117 patients (66.8%). A history of a head injury was reported at intake by 50 patients (28.4%). Of the patients with a history of a head injury, 34 (68%) were female, 16 (32%) were male, and 36 (72 %) had a history of cataplexy. Conclusion This study revealed 28.4% of patients diagnosed with narcolepsy reported a history of a head injury of varying degrees of severity. While direct causation cannot be declared, the association of a head injury and continued hypersomnia suggests further evaluation of narcolepsy may be beneficial. Support (if any) **No support for this study was given.